Racket is a set of tools for writing and running the PLT scheme
programming language. It includes a graphical IDE (drracket) that
features highlighting of the source of syntax and run-time errors,
support for multiple language levels, an algebraic stepper, objects,
modules, a GUI library, TCP/IP, and much more. It includes an
extensive, hyper-linked help system called Help Desk, available
from the Help menu, the plt-help command line tool, or through a
web browser.

The racket-textual port provides a text-only version of the Racket
environment without X11 dependencies.

WWW: http://racket-lang.org/